1. Field of Invention
This invention generally relates to systems and methods for processing distributed information.
2. Description of Related Art
Model-based diagnosis techniques use a model of a complex physical system, such as a printer or a vehicle, in order to diagnose the state of the system from the commands send to the system and the sensor observations received as a result. Such a system may comprise several subsystems, each made up of many components.
Model-based diagnosis techniques use a formal description of a device or physical system to automatically diagnose a system with a generic, reusable algorithm. A set of variables that represent relevant properties about a device to be diagnosed is defined. Next, a set of constraints that describe the normal and failure behaviors of the system is defined. The diagnostic algorithm then uses this constraint-based model to determine whether the system is operating in a normal manner, and, if not, what failures explain the abnormal behavior of the system.
However, the model-based diagnosis techniques are typically centralized. That is, a single diagnosis is performed for the entire system to be diagnosed. Thus, a central processor must resolve the global diagnosis problem, all observations must be routed to the central processor, and a single model of the entire system to be diagnosed must be created and stored on the central processor. Additionally, the centralized processor then needs to forward the diagnosis back to the various control processors within the physical system being diagnosed. This centralization represents a significant performance and development bottleneck.
This invention provides systems and methods that allow the diagnosis to be distributed among several communicating processors.
This invention separately provides systems and methods for dividing the centralized diagnostic system into separate subsystems.
This invention separately provides systems, methods and protocols for communicating between the separate diagnostic subsystems.
This invention separately provides systems and methods for assembling a global diagnosis of the system being diagnosed from the local diagnoses developed by each diagnostic subsystem.
Splitting a large exponential problem such as diagnosis into smaller problems solved using multiple subsystems result in diagnoses being found more quickly. In addition, separate diagnostic subsystems can perform diagnosis for each corresponding subsystem of the system being diagnosed and communicate that local diagnosis to form a global diagnosis for the entire system being diagnosed. This eliminates needing to forward all observations to a centralized computer, increasing robustness, decreasing communication costs, and reducing latency. This also allows the vendor of each subsystem being diagnosed to provide a diagnostic subsystem for that subsystem being diagnosed that is specifically designed to diagnose that subsystem. A common communication protocol allows the local diagnoses to be supplied to other diagnostic subsystems so that a global diagnosis can be generated.
These and other features and advantages of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of the systems and methods according to this invention.